Shift mechanism



FIG. 1 is a front perspective view of a shift mechanism showing our new design, the broken lines are for illustrative purposes only and form no part of the claimed design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is an enlarged side elevation view thereof, as seen from the left in FIG. 4; and,

FIG. 7 is an enlarged side elevation view thereof, as seen from the right in the FIG. 4. 

The ornamental design of a shift mechanism, as shown and described. 